El Nino effect: a periodic 'blip' in the usual global climatic characteristics caused by a short-term reduction in the intensity of the cold ocean current that normally exists off the west coasts of South America. It results in unusual patterns of temperature and rainfall and can lead to droughts and floods in certain parts of the worldGlacial period: a period of ice advance associated with falling temperaturesInterglacial: a period of ice retreat assoicated with rising temperatures Ice sheet: a large body of ice over 50,000km squared in extentIce cap: a smaller body of ice (less than 50,000km squared) usually found in mountainous regionsGlacier: a finger of ice usually extending downhill from an ice cap and occupying a valleyAccumulation: inputs to the glacier budget, such as snowfall and avalanchesAblation: outputs from the glacier budget, such as meltingSnout: the front of the glacierGlacier budget: the balance betwen the inputs (accumulation) and the outputs (ablation) of a glacierAbrasion: a process of erosion involving the wearing awya of the valley floor and sides (glaciers) and the shoreline (coastal zones)Plucking: a process of glacial erosion where individual rocks are plucked from the valley floor or sides as water freezes them to the glacierRotational slip: slippage of ice along a curved surfaceMoraine: sediment carried and deposited by the iceBuldozing: the pushing of deposited sediment at the snout of by the glacier as it advancesHummock: a small areas of raised ground rather like a large molehillCorrie: a deep depression on a hillside with a steep back wall, often containing a lakeArete: a knife-edged ridge, often formed between two corriesPyramidal peak: a sharp-edge mountain peakGlacial trough: a wide, steep-sided valley eroded by a glacierTruncated spur: an eroded interlocking spur characterised by having a very steep cliffHanging valley: a tributary glacial trough perched up on the side of a main valley, often marked by a waterfallRibbon lake: a long narrow lake in the bottom of a glacial troughLateral moraine: a ridge of frost-shattered sediment runningalong the edge of a glacier where it meets the valley sideMedial moraine: a ridge of sediment running down the centre of a glacier formed when two lateral moraines mergeTerminal moraine: a high ridge running accross the valley representing the maximum advance of a glacierDrumlin: an egg-shaped hill found on the floor of a glacial troughResponsible tourism: the idea of encouraging a balance between the demands of tourism and the need to protect the environmentSustainable management: a form of management that ensures that developments are longlasting and non-harmful to the environmentFragile environment: an environment that is easily damaged unbalanced and damaged by natural or human factorsAvalanche: a rapid downhill movement of a mass of snow, ice and rocks, usually in a mountainous environmentLoose snow avalanche: a powdery avalanche originating from a single pointSlab avalanche: a large-scale avalanche formed when a slab of ice and snow breaks away from the main ice pack
